Yes Oz does have a history of tsunami's @Kino.
You may remember from a post I did on WZ about a 'tsunami' like event that swept through/around Philip Island many years ago. If I remember correctly it was about 20 years ago. We were walking on the beach at Cowes and a rush of water came sweeping around the region and washed up against the blue stone walls, nearly washing one of my sons into the water around the pier. I had to grab him and get him to the steps on the beach wall. It scared the tripe out of us and in all my time on the island, I had never seen that happen before [in my 50+ years]. You could actually see the wall/line of water [probably under a metre high] sweeping around the island towards us.
I also meant to mention that I saw an asteroid crossing over Vic to the west on December 26th 2004. Some believe that an asteroid caused the horrific tsunami on the NE Indian Ocean. Some feel it was an earthquake. I have an open mind and am not sure one way or the other.......bless all those poor folks who lost their lives in that tragic event.
As I understand from what you're saying, the object you saw was not bright, but smoking grey, like in the linked photo?I meant to also add that that 'thing' I saw on 26th December 2004 is what is classed [apparently] as a grey asteroid/meteor. The following link pictures exactly what I saw from Chelsea Beach [Vic.] at 11am [Melbourne time]. This image is on Pinterest and is the top left image on the page link. https://www.pinterest.com.au/pin/679128818786635950/
It was an incredible site and a few of us [strangers to each other] turned and looked at each other with blank faces, wondering where it was heading at the time. It's trajectory, heading WNW, may have contradicted the direction of the 2004 tsunami effect on the coasts, but I can't confirm such.
Cheers again Duck.
Then it was not a large meteor or small asteroid.
Or, if an object entering the Earth's atmosphere was travelling slowly enough not to glow(unlikely), then any collision with the Earth would be low velocity, low energy and it would not be generating a large tsunami, like the one on 26th Dec 2004.